how to seal doors on grow room and what lighting 3x5

hey quick question im building a grow room im truing to have a closed environment how do you all seal closet doors? i havent bought the doors yet im open for any ideas this is a 3x5 scrog grow

also im trying to figure out if i should do 2 400w lights or 2 600 watt lights 55w per square foot or 80w per square foot is 80 over kill these will be air cooled 450cfm fan and very close to canapy i want to yield 2lbs ever 80 days will have 3 plants pertty much a larger rumpleforskin grow he dose a lb per 400w light

anyone ?

600w anything is gonna be hot. and a in a space thats 3x5x? i think it is gonna be a oven, thats a small space for only air cooled and all that light.

this is a scrog setup in a 3x5 8ft high area is 15 square feet i am ditching the 2 400w idea and its betwene 2 600w or a 1000w magnum xxxl the 2 600w lights will be 12000 lumens per square foot i think it may be over kill the 1000w will be around 10k lumens a square foot still over kill but i think would be good its going to be air cooled hoods c02 enriched and air conditioned i need to figure out what i should do on lighting asap how hard will the 1k light be to keep temps down. im trying to yield 2lbs off this space with a average yielding strain a tad over 2 ounces per squar foot with 4 plants its dj shorts seeds the strains called flo. id love for some help
oh here is a link to the strain if anyones interested its magical http://www.hempdepot.ca/seeds/dj_short/Flo.html